diff --git a/pyapr/reconstruction/APRSlicer.py b/pyapr/reconstruction/APRSlicer.py
index b0b1a30..d7abd18 100644
--- a/pyapr/reconstruction/APRSlicer.py
+++ b/pyapr/reconstruction/APRSlicer.py
@@ -67,6 +67,10 @@ def shape(self):
     def ndim(self):
         return 3
     
+    def __array__(self):
+        # allows things like np.max(APRSlicer)
+        return np.array(self.parts)
+    
     def astype(self, typespec):
         parts = type(type_to_particles(typespec))(np.array(self.parts).astype(typespec))
         dtype = typespec